PARENT SESSION
OOS 4: Organisms as Ecosystem Engineers: Conceptual Progress, Limits and Challenges.
Organized by: JP Wright and CG Jones
Monday, August 2, 8:00 AM to 11:30 AM, Meeting Room E 146.
A legacy of leaf ties: Engineering effects at multiple spatial scales.
Lill, John*,1, Marquis, Robert2, Lander, Katie3, Jones, Clive3, 1 George Washington University, Washington, DC, USA2 University of Missouri-St. Louis, St. L ouis, MO, USA3 Institute of Ecosystem Studies, Millbrook, NY, USA
ABSTRACT- Shelter-building caterpillars are a prominent part of the herbivore communities associated with many species of temperate broad-leaved trees. Beyond serving as feeding and resting sites for the larvae that build them, these constructs represent novel microhabitats that are secondarily colonized by a diverse array of forest arthropods. While a growing number of studies have found localized increases in arthropod abundance and diversity in these engineered habitat patches, their influences on arthropod community structure at larger spatial scales is poorly understood. By integrating the results of ongoing studies examining the creation and use of leaf ties on oaks, it is becoming clear that these engineered habitats increase species richness at both small and large scales but that the bulk of this effect is due to the use of leaf ties by habitat specialists that would otherwise be absent from the community (in the absence of shelters). At the scale of the patch or the individual tree, engineering increases richness by 15-30%; however, this effect diminishes at larger scales. Preliminary studies examining other co-occurring tree species suggest that the strong community-level effects of shelter-building found on white oak extend to other oak species and other Fagaceae, but are minimal on other unrelated plant hosts. Plant architectural traits appear to control resource flows (shelter availability) and may therefore be under selection by local populations of leaf-tying caterpillars.
Key words: herbivores, ecosystem engineering, community structure